U-tube well completion and method



March 9, 1965 c. J. coBERLY ETAL U-TUBE wEEL. COMPLETION ANO METHOD 8 Sheets-Sheet l Filed July 50, 1962 INVENTORS CLARENCE J. COEEELY,

VAL Kam/7' 5y THE/R AToRA/Eys HA RR/S, K/ECH, RUSSELL KERN March 9, 1965 c. J. coBERLY ETAL 3,172,469

U-TUBE WELL, COMPLETION AND METHOD Filed July 30, 1962 8 Sheets-Sheet 2 'G0 7 FIGO 6. l2/:071 w /04/03 l/a /06 /04 CLARENCE J. CoBERLs VAL Koel/T BY 7'HE/R ATTORNEYS' HAR/a, MECH, RUSSE/.L KERN March 9, 1965 c. J. coBERLY ETAL 3,172,469

U-T'UBE WELL COMPLETION AND METHOD 8 Sheets-Sheet 3 Filed July 30, 1962 mvENToRs CLA/25u65 J. Gaag/2L);

VAL Koen/7' r THE/R Arm/always HAR/21s, K/ECH, RUSSE/.L KERN March 9, 1965 c. J. coBERLY ETAL 3,172,469

U-TUBE WELL COMPLETION AND METHOD Filed July 30, 1962 INVENTORS CLARENCE J. CoERLY,

M41. K 0G07' ay wfg/e ATTORNEYS HARR/s, K/EcH, RUSSELL KERN March 9, 1965 c. J. COBERLY ETAL 3,172,469

U-TUBE wELL COMPLETION ANO METHOD Filed July so, 1962 a sneetsneet 5 .F.z'a 15.

INVENTOR5 CLARENCE J. COEEEL Y,

VAL. KOGUT 5) THE/1 ATM/@M5715 HABE/s, K/EcH, RUSSELL KERN March 9, 1965 c. J. coBERLY ETAL 3,172,469

U-TUBE wELL COMPLETION ANO METHOD Filed July 30, 1962 8 Sheets-Sheet 6 04 202 276 .Z-Tfz's. 16.

JG/U Eamon CKTH., N YC MV K C n, H

March 9, 1965 c. J. coBERLY ETAL 3,172,469

u-TUBE WELL. coMPLETIoNAND METHOD Filed July 50, 1962 8 Sheets-Sheet 7 376 302 FIG. 2J. 3% 304 IN VENTORS CLARENCE J. aaa-RLY,

VAL Koaur 344 5y THE/R ATTQRA/Exs HAR/a5, K/ECH, Russe/ 1. KERN Mach 9 1965 c. J. coBERLY ETAL 3,172,469

U-TUBE WELL COMPLETION AND METHOD Filed July 50, 1962 8 Sheets-Sheet 8 422 /02 .Pi/Eg?. 24. /061` /04 PTZG. 25.

mvENToRs CLARENCE J. CUBERLY, A v VAI. KOGUT `l BY THE/Q ATTRNEYS Il@ /44 /55 HARR/s, K/Echg RUSSELL. KERN United States Patent 3,172,469 p U-TUBE WELL COMPLETIN AND METHOD Clarence J. Coben-ly, San Marino, and Val Kogut, Long Beach, Calif., assguors to Kobe, Inc., Huntington Park, Calif., a corporation of California Filed July 30, 1962, Ser. No. 213,434 11 Claims. (Cl. 16o- 23) The invention relates in general to oil well completions and has as its basic object the provision of a completion capable of producing oil efficiently and at ade,i quate rates even in `wells of very small diameter, although the invention may be practiced in wells of larger diameter also.

In accordance with current practice, oil wells are being completed with cas-ings having an outside diameter of as little as 2%; inches, and outside diameters as small as 2% inches are being considered. With such small casings, producing wells by presently accepted means is quite difficult, particularly where the producing means is a fluid operated pumping system requiring two or more tubings within the casing.

With the foregoing as background, a primary object of the invention is to provide an oil well completion which is capable of producing oil eiiiciently and at adequate rates, even in very small holes, by various methods, including flowing the well with or without gas lifting, pumping the well with a rod operated pump, pump-ing the well with a huid operated pump, and the like. A related object of extreme importance is to provide a completion useable in small holes which separates the oil and gas producedby the well very effectively so that maximum volumetric eliiciency is achieved by equipment used to pump the Well, whether such equipment be rod opera-ted, uid operated with multiple tubings, or the like.

The foregoing principal objectives are achieved in part by utilizing the 'basic concept of a casingless completion involving a tubing system which includes at least two side-by-side or parallel tubings cemented in place, as dis closed in Patent No. 2,939,533, granted June 7, 1960 to Clarence J. Coberly. As more fully discussed in that patent, such a completion has various basic advantages, among these being smaller well bores with accompanying reductions in drilling costs, the elimination of casing costs (except for surface casings where required to protect underground fresh water supplies, or the like), superior support for the surrounding formations as the result of cementing the tubing system in place, and so forth.

Another and extremely important principal object of the invention is to provide an oil well completion, and particularly a casingless, cemented-in-place completion of the nature hereinbefore outlined, wherein the tubing system is, `in effect, U-shaped and wherein fluid from the formation to be produced is admitted into an inlet tubing forming part of the U-shaped system at a level above the lower end of such inlet tubing. This achieves important advantages which will be considered hereinafter.

Another object of the invention is to establish communication between the selected producing formation and the inlet tubing, after the U-shaped tubing system has been cemented in place in the well, by perforating the inlet tubing, and the cement surrounding it, at the level ICC of the selected producing formation and above the lower end of the inlet tubing, utilizing any suitable perforating equipment. With this procedure, itis necessary to drill the well at least into the producing formation a suliicient distance to locate the lower end of the U-shaped tubing system below the level at which the inlet tubing is to be perforated. Normally, unless the selected producing formation is extremely thick, the well must be drilled through the producing formation.

It will be lunderstood that, in accordance with the invention, the U-shaped tubing system is cemented in place at the level of the producing formation (and below the producing formationv in the event that the hole extends therethrough), and isv also cemented in place above the producing formation as required to supportvthe wall of the hole. In some instances, the tubing system may be cemented in place all the way to the surface, or atleast to any surface casing which may be used.

With a completion ofthe foregoing nature, the well may be produced by flowing it through the perforated, inlet tubing, or through a parallel tubing which forms the other arm of the U-tube, or both, utilizing the natural formation pressure. In the event that the formation pressure is insufficient to, or declines to a value insuiiicient to, produce the well by natural llow, the oil column or columns may be lightened by gas injection, utilizing conventional gas lifting techniques. Por example, gas may be injected into the inlet tubing through a concentric tubing therein, or gas may be injected into the inlet tubing through the tubing which forms the other arm ofthe U-tube.

In the event that a satisfactory oil production rate cannot be achieved by natural tlow and/or gas lifting, either initially, or after partial depletion of the well, an important object of the invention is to install a pump, such as a rod operated pump, or a iluid operated pump, in the tubing which forms the second arm of the U-tube, such tubing being referred to as a pump tubing hereinafter for convenience.

When a pump is installed in the pump tubing, it draws oil into its inlet from the inlet tubing through a fluid interconnection between the pump and inlet tubings provided by a bottom hole assembly to which the lower ends of these tubings are connected, such bottom hole assembly providing a pump housing in alignment with and in communication with the lower end of the pump tubing.

Since the level at which the inlet tubing and the surrounding cement are perforated into communication with the selectedk producing formation is above the lower end of the U-shaped tubing system, the oil drawn into the inlet of the pump in the pump tubingA must flow downwardly through the inlet tubing from the level of the perforations therein. At the same time, gas produced by the selected formation flows upwardly through the inlet tubing from the level of the perforations therein and is drawn off at the surface. Thus, the liquid and gaseous components of the well fluid entering the inlet tubing flow in opposite directions in the inlet tubing, the gaseous components ilowing upwardly to the surface and the liquid components owing downwardly to the lower end of the inlet tubing and thence to the inlet of the pump in the pump tubing.

With the foregoing construction, by locating the lower end of the U-tube an adequate distance, e.g., 50 to 100 feet, or more, below the perforations through which the well liuid enters, excellent gas-oil separation is obtained, enabling the pump to operate at maximum volumetric eiiiciency, which is an important feature of the invention.

It will be understood that'if the well involves two or more potentially productive formations, the Well is drilled deep enough to locate the bottom of the U-tube a distance below the lowermost producing formation suiiicient to achieve the desired oil-gas separation. Two or more formations may be produced simultaneously where commingling is permissible. Alternatively, the inlet tubing may be perforated only opposite the formation to be produced initially, being perforated opposite another producing formation after depletion of the rst. Alterna.- tively, the inlet tubing may be perforated opposite all of the producing formations, and any which are not to; be produced may be packed olf. In any event, the tub-- ing system is cemented in place at least to a level above the shallowest productive formation.

An important object of the invention is to provide a.

method of cementing the tubing system in place which.

involves circulating the cement downwardly through one. arm of the U-tube, preferably the inlet tubing, and discharging the cement through an opening adjacent the lowerV end thereof. Another object in this connection is to prevent the cement from flowing up the other arm of the U-tube, and incidentally from plugginginterconnecting passages in the bottom hole assembly, by means of a plug which is `seated below the cement discharge opening and which is circulatable out of the well through the inlet tubing by introducing mud, water, or other suitable uid,v therebeneath through the other arm of the U-tube, eg., the pump tubing.-

Another objectis to purge the inlet tubing of cement by circulating another removable plug down the inlet tubing after the cernenting operation has been completed, this second plug coming to rest on top of the first plug mentioned. Both plugs can then be circulated out of the well through the inlet tubing simultaneously by uid injected into the opposite arm of the U-tube'.

Still another important object of the invention is to provide a U-shaped tubing system which includes, in addition to the inlet and pump tubings mentioned, an additional tubing or tubings for use With a fluid operated pumpl positioned in the pump housing at the lower end of the pump tubing, such additional tubing or tubings normally being smaller than the inlet and pump tubings. A related object is to provide a fluid operated pump of the type which is capable of being circulated into and out of the well, through the pump tubing, hydraulically.

More particularly, an object of the invention in connection with the foregoing is to provide a tubing system whichE includes a third tubing connected at its lower end tothe bottom hole assembly in communication with the uid operated pump when the pump is in its operating position in the pump housing. Such third tubing may either be' al supply tubing for conveying operating fluid under pressure for operating the pump downwardly in the well to' the pump when the pump is in its operating position, or it may be a production tubing for conveyingupwardly to the surface production fluid discharged by the pump when the pump is in operation.

Still another object is to provide a tubing system which is either an open system or a closed system. In the former case, the production fluid discharged by the pump and the spent operating tluid discharged thereby are commingled and conveyed to the surface through the production tubing, the latter being either the pump tubing or a third tubing. In the case of a closed system, there is a fourth tubing for returning the spent operating fluid to the surface independently of the production uid from the Well. Such fourth tubing is also connected at its lower end to the bottom hole assembly and communicates with the operating fiuid exhaust of the pump when'the pump is in its operating position.

A further object is to provide a three-tubing or fourtubing system wherein all of the tubings are cemented in place in the Well in parallel or side-by-side relation.

Anotherobject is to provide a three-tubing or four- :tubing system wherein the inlet and pump tubings are cemented in place in parallel relation, and wherein the I third tubing of a three-tubing system, or one of the additional tubings of a four-tubingsystem, is concentrically disposed Within the inlet tubing in appropriate communication with the pump when the latter is in operation. Another object in this connection is to provide a concentric tubing within the inlet tubing which may be stabbed into 4a suitable fitting in the bottom hole assembly at the lower .end of the inlet tubing after the tubing system has been cemented in place by cement circulated in through the inlettubing, and after the inlet tubing and the surrounding cement has been perforated to establish communication with the desired producingk formation or formations. This concentric tubing may beused as the supply tubing, the production tubing,.or the return tubing, depending upon the particular embodiment of the invention being considered.

It will be understood thatwith the basic U-tube cornpletion of the invention, various completing, servicing .and/or remedial operations, such as hailing, cementing, perforating, swabbing, acdizing, hydraulic fracturing, and the like, may be carried out, as Vmore fully discussed in the aforementioned patent.

The foregoing objects, advantages, features and results of the present invention, together with various other objects, advantages, 4features andY results thereof which will be evident to those skilled in the oil well completing and producing art in the light of this disclosure, may be .achieved with the exemplary embodiments of the invention described in det-ail'hereinafter and illustrated in the accompanying drawings, wherein:

FIGS. 1,y 2 and 3 are semidiagrammatic vertical sectional views showing the basic casingless, cemented-inplace, U-tube oil well completion of the invention;

FIG. 4 is a horizontal sectional view taken along the: arrowed line 4--4 of FIG. 1;

FIG. 5 is a horizontal sectional view of an oil well, with one embodiment of a U-shaped tubing system of the. invention set therein, FIG. 5 being taken as indicated by .the arrowed lineS-S of FIG. 6;

FIGS. 6, 7 and 8 are vertical sectional views, each taken along the irregular arrowed line 6 6 of FIG. 5, iliustrating the steps involved in cementing the U-shaped tubing system of the invention in place, purging the inlet. tubing of cement, and perforating the inlet tubing;

FIG. 9 is a vertical sectional'view of an oil well com pletiofn of the invention-which comprises a partially concentric, U-shaped, closed tubing system for a iluid operat ed pump of the type which is hydraulically circuatableinto and out of the Ywell through a pump tubing of the tubing system, FIG. 9 being taken along the irregular arrowed line 9-9 of FIG. l0;

FIG. 10 is a horizontal sectional View taken along the arrowed line Ill-loof FIG. 9;

FIG. 11 is a downward continuation of FIG. 9 and is taken along the irregular arrowed lines 11-11 of FIGS. l2 and 13 FIGS. l2, 13 and V14 are horizontal sectional views respectively taken along the arrowedlines i12- 12, 13--13 and 14-14 of FIG. 11;

FIG. 15vis a downward continuation of FIG. l1 and ilstaken along the irregular arrowed line S--IS of FIG.

FIGS. 16 and 17 are horizontal sectional views respectively taken along the arrowed lines 11S- I6 and 17--17 of FIG. 15

FIG. 18 is a vertical sectional View of an all parallel, U-shaped, closed tubing systemof the invention, FIG. 18 being taken along the irregular arrowed line It-IS of FIG. 19;

FIGS. 19 and 20 are horizontal sectional views respectively taken along the arrowed lines 19-19 and Ztl-20 of FIG. 18;

FIG. 21 is a vertical sectional view, taken along the arrowed line 21-21 of FIG. 22, of a partially concentric, U-shaped, open system of the invention;

FIGS. 22 and 23 are horizontal sectional Views respectively taken along the arrowed lines 22-22 and 2.3-23 of FIG. 21;

FIG. 24 is a vertical sectional View of an all parallel, U-shaped, open system of the invention; and

FIG. 25 is a vertical sectional view of another all parallel, U-shaped, open system of the invention.

FIGS. 1 to 4.-Basz'c U-tube completion These figures of the drawings illustrate, in a semidiagrammatic manner, the basic casingless, cemented-inplace, U-tube oil well completion of the invention, a twotubing system being shown.

The numeral designates a well drilled through producing formations 32, 34 and 36. Except for a surface casing 38 which may be required in some areas to prevent contamination of underground fresh water supplies, or the like, the well 30 is uncased in accordance with the practice of the aforementioned Patent No. 2,939,533.

Suspended in the uncased well 30 from a well head 40 is U-shaped tubing system or U-tube 42 of the invention. T his U-tube includes two side-by-side or parallel tubings 44 and 46 interconnected in fluid communication at their lower ends and connected at their upper ends to a tubing head 48 containing suitable conventional control means, such as control valves, and the like. For reasons which will become apparent, the tubing 44 will be referred to hereinafter as an inlet tubing, and the tubing 46 will occasionally be referred to as a pump tubing.

The U-shaped tubing system 42 is cemented in place in the uncased well 30 by a body of cement 56 which surrounds the tubings 44 and 46 and which cements off the productive formations 32, 34 and 36. Preferably, the body of cement 50 extends Afrom the bottom of the weil 30 upwardly at least to a level above the uppermost or shallowest productive formation 32. However, the body of cement 50 may extend upwardly in the well 3i) all the way to the surface, or at least into the lower end of the surface casing 38, if used. The level to which the body of cement 50 extends upwardly above the uppermost producing formation 32 depends on the nature of the formatiens thereabove and the extents to which they require support. It will be understood that while the well 30 is shown as drilled through three producing formations, the linvention is not limited to any particular number of producing formations, being equally applicable to a well having but one producing formation. In any event, the well s filled with cement to a level at least slightly above the shallowest producing formation, which may be the only producing formation.

After the U-tube 42 is cemented in place in accordance with the foregoing, the inlet tubing 44 and the cement 50 surrounding it are perforated, utilizing any suitable perlforating equipment, to establish uid communication beytween the inlet tubing and one or more of the productive 'formations 32, 34 and 36. In FIGS. 1 to 4 of the drawings, the inlet tubing 44 and the surrounding cement 5 6 are shown as perforated to provide communication with all three of the productive formations, thel perforations into the productive formations 32, 34 and 36 being identified by the reference numerals 52, 54 and 56, respectively. If oil from two or more of the formations 32, 34 and 36 can be commingled, the corresponding perforations 52, 54 and 56 are left open. Otherwise, only the perforations into fthe particular formation to be produced are left open. In :the particular construction illustrated, only the formation 36 is to be produced, the perforations 52 and 54 leading to the respective formations 32 and 34 being closed by :suitable tubular packers 58 and 60 set in the inlet tubing 44. If, after partially or completely depleting the formation 36, it is desired to produce one of the formations 32 `and 34, the corresponding one of the packers 58 and 60 is removed, and the formation 36 is shut in with a similar packer. It will be understood, of course, that as an alternative to the foregoing procedures, the inlet tubing 44 can be perforated originally only opposite the formation to be produced initially. Later, the inlet tubing 44 can be perforated opposite the next formation to be produced, shutting in the first formation, or leaving it open, as circum-I stances require.

The balance of this discussion of t-he semidiagrammatic embodiment of the invention which is illustrated in FIGS. 1 to 4 of the drawings will be restricted to producing the formation 36. It will be understood that similar procedures may be utilized in connection with the other producing formations 32 and 34.

Referring to FIG. l of the drawings, the well 30 may be produced by flowing it, utilizing the native pressure present in the productive formation 36. FIG. l shows production up the inlet tubing 44, the flow of oil, and other liquids if present, being indicated by the solid arrows 62, and the flow of gas being indicated by the dotted arrows 64. While upward flow is shown through the inlet tubing 44 only, it will be understood that the well 30 may be produced by flowing it through both of the tubings 44 and 46. ln other words, part of the well fluid entering the inlet tubing 44 through the perforations 56 may flow downwardly through the inlet tubing to the interconnection between the two tubings, and then upwardly through the second tubing 46.

In vthe event that the formation pressure is insufficient to, or becomes insucient to, achieve an adequate production rate, the well 36 may be produced by, or its production supplemented by, gas lifting. As shown in FIG. 2 of the drawings, gas may be injected into the upper end of the second tubing 46, the downward flow of gas being designated by the dotted arrows 66. Such gas flows downwardly to the interconnection between the tubings 44 and 46, and then upwardly through the inlet tubing 44 to lighten the liquid column in such tubing and assist, or produce, the desired upward flow of oil, and other liquids which may be present7 through the inlet tubing. The solid arrows 68 in the inlet tubing 44 in FIG. 2 designate upward liquid flow, while the dotted arrows 70 therein designate the upward flow of injected and native gas. If desired, the injected gas may enter the lower end of the inlet tubing 44 through a suitable gas lift device, not shown, installed in the tubing 46 adjacent the lower end thereof.

Turning now to FIG. 3 of the drawings, a rod pump 72 may be installed in the tubing 46 adjacent the lower end thereof in the event that the well 3i) cannot be produced at an adequate rate by natural flow and/or gas lifting. Alternatively a fluid operated pump can be substituted for the rod pump 72, as will be described in more detail hereinafter.

The lower ends of the tubings 44 and 46 are a substantial distance below the lowermost productive formation, e.g., the productive formation 36. It will be understood that the well 30 is drilled deep enough to permit locating the interconnection between the lower ends of the ltubings 44 and 46 below the lowermost producing formation.

With the foregoing installation, the oil, and any other liquids present, which are drawn into the inlet of the pump 72, must first flow downwardly through the inlet tubing 44 from the perforations 56, and then upwardly to the inlet of the pump, as indicated by the solid arrows 74. The liquid discharged by the pump 72 flows upwardly to the surface through the pump tubing 46, as indicated by the solid arrows 76. Meanwhile, any gas entering the inlet tubing 44 through the perforations 56, and any gas separating. out of the oil flowing downwardly through the inlet tubing 44, flows upwardly to the surface through the inlet tubing, as indicated by the dotted arrows 78. The interconnected lower ends of the tubings 44 and 46 are located a sufficient distance below the lowermost productive formation, c g., the productive formation 36, to achieve sufficient gas-oil separation in the inlet tubing 44 lto permit the pump 72 to operate at a satisfactory volumetric eiiciency. The distance between the lowermost perforations 56 and the interconnected lower ends of the tubings 44 and 46 necessary to achieve adequate gas-oil separation depends on the conditions encountered in the particular well being produced. For example, this distance may be of the order of 50 feet to 100 feet, or more.

Thus, it will be apparent that the basic U-tube concept of the present invention inherently acts as a gas-oil separator to improve :the volumetric eficiency of the pump 72 in the second tubing 46 when the lowermost perforations in the first or inlet tubing 44 are located a sufficient distance above the interconnected lower ends of the tubings, which is an important feature of the invention.

FIGS. to 8.-*Permcznent wel] completion technique These figures illustrate the procedure of the invention of cementing in place in a well 100 a tubing system 102 which is the same as the U-tube 42 in principle, but which` includes a third. tubing in parallel or side-by-side relation with the two tubings that form the U-tube, and which may include a fourth tubing within and concentric with the inlet tubing of l'the system, all as will be discussed-in more detail later.

(The tubing system 102 forms the basic tubing system of the embodiment of FIGS. 9 to 17 of the drawings, and forms the respective tubing systems of the embodiments of FIG. 24 and FIG. 25 thereof. Also, the tubing system 102 is generally similar to the tubing systems of the embodiments of FIGS. 18 to 2O and FIGS. 21 to 23. Consequently, the description in this section of this specification pertaining to the installation of the tubing system 102 is applicable to the tubing systems of the various embodiments of FIGS. 9 to 25 as well.)

The tubing system 102 includes parallel inlet and pump tubings 104 and 106 the lower ends of which are connected to and interconnected in fluid communication by a bottom hole assembly 108 to provide the same basic U-tube arrangement as the `U-tube 42 hereinbefore described in connection with FIGS. 1 to 4 of vthe drawings. In addition, the tubing system 102 includes a third .parallel tubing 110 the lower end of which is also connected to the bottom hole assembly 108, the function of this third tubing being discussed hereinafter. The lower ends of the three tubings104, 106 and 110 are connected to the upper end of the bottom hole assembly 108 in any suitable manner, as by threading them thereinto.

The bottom hole assembly 108 provides a pump housing 112 aligned with and communicating with the lower end of the pump tubing 106. The pump housing 112 is adapted to receive therein a fluid operated pump, to be described later, lof a size to be circulated through the pump tubing 106, between the surface and an operating position in the pump housing 112, hydraulically. At the lower end of the pump housing 112 is a seat 114 for a conventional inlet fitting 116 on which the lower, inlet end of a fluid operated pump is seatable in the usual manner, the inlet fitting 116 containing the usual standing valve, not shown. The pump housing 112 is also provided therein with an upper, sealing collar 118 and a lower, sealing sleeve 120 both engageable in a tluid-tight manner by a fluid operated pump circulated into the pump housing and seated on the inlet fitting 116.

The bottom hole assembly S is provided therein with a bypass passage 122, for production fluid discharged by a fluid operated pump in the pump housing 112, which is connected to the interior of the pump housing 112 adjacent the upper end of the sealing sleeve 120 by a lateral passage 124, and is connected to ports 126 in the sealing S collar 118 by a lateral passage 128. As will be described in more detail hereinafter, the passages 122, 124 and 128 and the ports 126 provide a production uid bypass around a fluid operated pump in the pump housing 112.

The inlet tubing 104 communicates at its lower end with a lateral, cement-discharge port 130 in and leading to the exterior of the bottom hole assembly 108. The lower end of the inlet tubing 104 also communicates with a tubular tting 132 in the bottom hole assembly 108, this tubular fitting being provided with a central, axial bore or passage 134 therethrough which is encircled by an upwardly facing, annular seat 136. The axial passage 134 communicates through a lateral passage 138 with radial ports through `the sealing `collar 118 below the radial ports 126. Paralleling the axial passage 134 in the tubular itting V132 is a longitudinal passage 142 therein. The longitudinal passage 142 in the tubular fitting 132 communicates with the interior of this fitting above the annular seat 136,` and communicates at its lower end with the lower end of the axial passage 134. The lower ends of the axial and longitudinal passages 134 and 142 communicate with the upper end of a passage 144 inthe bot-tom hole assembly 10S, the passage 144 communicating at its' lower end with the lower end of the pump housing 112 belowthe Vinlet fitting 116. As will be discussedin more detail hereinafter, well uid admitted into the inlet tubing 104 can flow downwardly through the upper port-ion of the tubular` fitting 132, the longitudinal passage 142 therein, the passage 144 in the bottom hole assembly 108, and then upwardly through the inlet fitting 116 into a iluid operated pump within the pump housing 112 at the lower end of the pump tubing 106. This interconnectonbetween the inlet and pump tubings 104 and 106provides the same basic U-tube arrangement as that hereinbefore discussed in connection with FIGS. 1 to 4 of the drawings.

The lower end of the third tubing 110 communicates with the upper end of a passage 146 in the bottom hole assembly 108. The passage 146 communicates intermed-iate its ends with a lateral passage 148 leading to radial ports 150 in the sealing collar 11S below the ports 140 therein. `The passage 146 is provided adjacent its lower end with an upwardly facing, annular seat 152, the bottom hole assembly 108 being provided below this annular seat with a lateral passage 154'which connects the lower end of the passage 146 to the interior of the sealing sleeve 120 just above the inlet fitting 116.

Considering the manner in which the tubing system 102, which includes the bottom hole assembly 108, is installed in the well 100, the first step is to set the tubing system in the well with the lower end of the bottom hole assembly 108 sufficiently below the formation to be produced yto provide the desired gas-oil separating effect in the VU-tube formed by the inlet and pump tubings 104 and 106, the productive formation being indicated. by the reference numeral in FIGS. 7 and 8 of the drawings. It will be understood that the well 100 is drilled to the depth necessary to permit locating the lower end of :the bottom hole assembly 108 the necessary distance below theproducing formation 160.

After the tubing system 102Vhas been set in the well 100` as outlined above, cement 158 is pumped down the inlet tubing 104 from the surface and escapes into the well 100 'through the cement discharge port 130 in the bottom hole assembly 108. A plug or stop 162 seated on the annular seat 136 within the tubular fitting 132 acts to prevent the flow of cement downwardly into the bottom hole assembly 108 below the discharge port 130, the upper endl of the plug preferably being substantially ilush with the bottom edge of the discharge port. The plug 162 is of a size to permit it to be circulated through the inlet tubing 104 `to the surface upon completion of the cementing operation. The plug 162 could be installed after installation of the tubing system 102 by cir- 9 culating it downwardly through the inlet tubing 104 onto the annular seat 136. However, it is preferable to install the plug 162 before setting the tubing system 102 in the well to insure a cement-tight barrier below the discharge port 130.

The cement pumped downwardly through the inlet tubing 104 and escaping through the discharge port 130 envelops the various components of the tubing system 102, including the bottom hole assembly 108, and encases them in cement. To promote more even distribution of cement, the bottom hole assembly 108 is surrounded by a depending skirt 164 which is secured to the upper end of the bottom hole assembly 108 and extends downwardly substantially to the lower end thereof. As indicated by the arrows in FIG. 7 of the drawings, the skirt 164 insures a uniform cement flow entirely around the tubing system 102.

Cement is pumped downwardly through the inlet tubing 104 until it has completely filled the well 100, and encased the tubing system 102, to the desired level, the cement flowing upwardly between the wall of the well and the tubing system, as indicated by the arrows in FIG. 7 of the drawings. As previously explained, the well 100 is filled with cement at least to a level above the shallowest formation to be produced, and may be filled all the way to any surface casing that may be used, or all the way to the surface of the ground. Any suitable equipment may be used to determine the level to which the cement has risen in the well 100.

Once the cement level has moved upwardly to the desired depth, a swab or clean-out plug 166 is insented into the upper end of the inlet tubing 104 and is circulated downwardly through the inlet tubing by any suitable fluid, such as mud or water, introduced into the inlet tubing thereabove. The swab 166 thus purges the inlet tubing 104 of cement by displacing any cement in the inlet tubing between it and the plug 162 out through the cement discharge port 130. Ultimately, the swab 166 comes to rest on top of the plug 162.

Subsequently, after the cement has set sufficiently, the plug 162 and the swab 166 are circulated out of the well through the inlet tubing 104 by introducing a suitable fluid under pressure into one or the other, or both, of the tubings 106 and 110. The fluid used to circulate the plug 162 and the swab 166 out of the well enters the inlet tubing 104 through various of the passages in the bottom hole assembly 108, and may flow directly into the inlet tubing from the pump tubing 106 by way of the U-tube connection between these tubings in the event that the inlet fitting 116 for a uid operated pump is not in place. It will be understood that the inlet fitting 116 may be installed prior to setting of the tubing system 102 in the well, but that it may also be installed, and preferably is installed, later by dropping it down or lowering it down the pump tubing 106.

After removal of the plug 162 and the swab 166, any suitable perforating equipment, not shown, may be lowered down the inlet tubing 104 to the level of the productive formation 160, and then actuated to form perforations extending through the inlet tubing and the surrounding cement into the producing formation. It will be understood that conventional means are available for controlling the orientation of such perforating means so that the perforations 168 clear the tubings 106 and 110.

With fluid communication thus established between the producing formation 160 and the interior of the inlet tubing 104 through the perforations 168, the well may be produced by flowing it, by flowing it with gas lifting, by gas lifting alone, or by pumping. Pumping of the well 100 by means of a uid operated pump installed in the pump housing 112 will now be considered in the next scction of this specication.

10` FIGS. 9 to 17.--Cl0sed system with three parallel tubings and one concentric tubing and with production up large tubing Briey stated, these figures of the drawings illustrate a permanent completion utilizing the tubing system 102, with its three parallel tubings 104, 106 and 110, and utilizing a removable fourth, supply tubing 176 concentrically set in the inlet tubing 104, production being up the large pump tubing 106.

More particularly, the pump housing 112 of the tubing system 102 is shown as containing a fluid operated pump having a well fluid inlet y172, FIG. 15, which is seated onA the inlet fitting 116. The engine section of the pump 170 is provided with an operating uid intake 174, FIG. 1l, which receives operating fluid, such as clean crude oil, under high pressure from the supply tubing 176, the latter, as indicated above, being concentrically disposed within the inlet tubing 104. Y The supply tubing 176 is installed in the inlet tubing 104 after the tubing system 102 has been cemented in place and the inlet tubing has been perforated, as hereinbefore described. The supply tubing 176 is provided at its lower end with a tubular fitting 178 which is stabbed into the central, aXial passage or bore 134 in the tubular fitting 132 and which is seated on the annular seat 136. Radial ports in the fitting 178 establish communication between the interior of such fitting and the lateral passage 138 leading to the radial ports 140 in the sealing collar 118. The operating iluid intake 174 of the pump 170 registers with the radial ports 140 so that operating Huid under pressure from the supply tubing 176 reaches the operating fluid intake 174 of the pump by way of the tubular fitting 178, the radial ports 180 therein, the lateral passage 138 in the bottom hole assembly 108, and the radial ports 140 in the sealing collar 118.

The pump 170 is provided with an operating uid exhaust 182 which communicates with the radial ports 150 in the sealing collar 118 when the pump is in its operating position. Thus, spent operating fluid discharged through the operating fluid exhaust 182 enters the tubing 110 by way of the radial ports 150, the lateral passage 148 in the bottom hole assembly 108, andthe vertical passage 146 therein. In this instance, the tubing 110 thus acts as a return tubing for conveying the spent operating fluid to the surface. y

The pump 170 is provided with a production fluid outlet 184, FIG. l5, which communicates, through an annular clearance between the pump 170 and the pump housing 112, with the lateral passage 124 leading to the lower end of the production uid bypass passage 122. Production fluid discharged by the pump 170 flows from the bypass passage 122 back into the pump housing 112, above the operating uid intake and exhaust 174 and 182, by 'way of the lateral passage 128 and the ports 126 in the :sealing collar 118, as shown in FIG. 11. At this point, the production uid discharged by the pump 170 enters a tubular packer mandrel 186 through production fluid inlet vports 18S therein. The ports 188 are located below the vusual downwardly facing packer cups on the packer :mandrel 186, such packer cups being engageable with the pump tubing 106 in a fluid-tight manner. As shown in FIG. 9 of the drawings, the production fluid leaves the packer mandrel 186 at a point above the packer cups 190 through production fluid outlet ports 191, and flows upwardly to the surface through the pump tubing 106. In this instance, the pump tubing 106 acts as the production tubing of the system. Normally, the pump tubing 106 will be one of the largest tubings of the tubing system 1102, preferably being at least as large as the inlet tubing 104. Consequently, the resistance to upward flow of the production fluid discharged by the pump 170 is minimized to assure maximum production from the well 100.

In order to block upward flow through the tubular packer mandrel 186 when it is desired to circulate the pump 170 upwardly through the pump tubing 106 to the surface, an elongated valve member 192 is caused to move upwardly into engagement with an annular seat 193 in the mandrel above the production iuid inlet ports 188 therein. The valve member 192 is provided adjacent its lower end with an upwardly facing annular shoulder 194 which is normally exposed to the operating fluid pressure in the operating fluid intake 174. The latter includes radial ports 195 which communicate with an annular clearance 196 around the valve member 192 above the shoulder 194, this valve member having radial ports 197 therein which convey operating duid from the clearance 196 into an axial passage 198 in the valve member leading downwardly into the engine section of the pump 170. Below the annular shoulder 194 on the valve member 192 is a downwardly facing annular shoulder 199 thereon which is exposed to the spent operating duid pressure in the operating .iiuid exhaust 182 and against which is seated a compression spring 189 for biasing the valve member upwardly toward its seat 193.

With the foregoing construction, as long as the pump 170 is in operation, the operating fluid pressure acting o-n the annular shoulder 194 holds the valve member 192 olf its seat 193, against the action of the spring 189, so that the production iiuid may flow upwardly through the packer mandrel 186 as previously described. However, when it is desired to circulate the pump 170* out of the well hydraulically, in a manner to be explained, the Operating uid pressure. is no longer applied to the shoulder 194 so that the spring 189 seats the valve member 192 to prevent upward bypassing of the packer cups 190 by the iluid used to circulate the pump out of the well.

It will be understood that the well tiuid entering the pump 170, the production fluid discharged thereby, the operating tiuid entering the pump, and the spent operating iiuicl discharged thereby, are all separated from each other by suitable seals. Por example, the pump 170 oarries seals engage-able with the sealing collar 118 and the sealing sleeve 120, and the tubular fitting 178 at the lower end of the supply tubing 176 carries suitable seals engageable with the tubular fitting 132 in the bottom hole assembly 108. These seals are all shown in the drawings, but it is not thought necessary to describe them in detail.

Considering the oper-ation of the embodiment of the invention illustrated in FIGS. 9 to 17 o-f the drawings, after the tubing system 102 has been cemented in place in the well 100 and the linlet tubing 104 has been perforated to establish communication with the productive formation 160, the supply tubing 176 is inserted into the inlet tubing 104- until the tubular fitting 178 at the lower end thereof is stabbed into the tubular fitting 132 in the bottom hole assembly 108 and is seated on the annular seat 136. Also, the'inlet fitting 116 is installed on its seat 114 through the pump tubing 106, if it was not installed previously.

Then the pump 170 is -circulated downwardly through the pump tubing 106 into its operating position in the pump housing 112, the well fluid inlet 172 of the pump seating on the inlet fitting 116. As is conventional in uid operated pumping systems of this general character, the fluid in the pump tubing 106 beneath the pump 170 is displaced to the surface through one or more of the remaining tubings of the tubing system 102.

With the pump 170 installed, operating iiuid under .the supply tubing 176 to the lower end of the tubing system 102, and then flow upwardly through `the inlet litting 116 into the inlet 172 of the pump 170. The gaseous components of the Well iiuid flow upwardly to the surface through the annulus between the inlet and supply tubings .104 and 176. As previously explained, the lower end of the tubing system 102 is located suiciently below the productive formation to insure satisfactory separaL tion of the gaseous components of the well uid from the liquid components thereof as such liquid components flow downwardly from the perforations 168, which is an important feature of the invention.

The production duid discharged from the production fluid outlet 18dV of the pump 170 enters the pump tubing 106 above the pump by Way of the various interconnecting ports and passages described, the valve member 192 being unseated by the operating fluid pressure. Thus, the pump tubing 106, in this embodiment, acts as a relatively large production tubing for conveying the production iiuid to 'the surface with a minimum of resistance.

When it is desired to remove the pump from the well, the supply tubing 176 is closed at the surface, and fluid under pressure is introduced into the return tubing 110 with the pump tubing 106 open. The fluid introduced into the return tubing 110 in this manner enters the pump housing 112 below the pump 170 through the vertical passage 146 and the lateral passage 154, and unseats the pump by acting on an annular area of the pump (equal .to the difference between the external cross-sectional area thereof and the cross-sectional area thereof in engagement with the inlet fitting 116. Thereafter, fluid introduced beneath the pump acts on the entire cross-sec tional area of the pump to displace it upwardly through the pump tubing 106 to the surface, the packer cups 190 engaging the pump tubing 106 in a fluid-tight manner to prevent bypassing of fluid past the pump. At this time, the valve member 192 is seated to prevent bypass- :ing of the packer cups 190. Once the pump has been unseated and displaced upwardly sufficiently that the vari- :ousseals thereon disengage the sealing collar 118 and the seal-ing sleeve 120, addition-al uid may be introduced beneath the pump through the supply tubing 176 to circulata it to the surface at a faster rate.

FIGS. .18 to 20.-Closed system with four parallel tubmgs and with production up large tubing Summarizing this embodiment, it includes a tubing sys- Item 2 02 which is similar to the closed tubing system 102 path its fourth tubing 176, except that the fourth tubing, iinstead of :being concentric, is parallel to the other three and 1s cemented in place also. Production is up the large pump tubing.

For convenience, the various components of the tub- 1ng system 202 are identified by reference numerals higher by o ne hundred than the reference numerals used to identify :corresponding components of the tubing system 102. In view of this system of identification, and in view of the over-all similarity of the tubing system 202 to the tubing system 102, it will not be necessary to describe the tubing system 202 in detail, and only the differences between it and the tubing system 102 will be pointed out.

The principal difference between the tubing systems 202 and 102 is that, in the tubing system 202, the four tubings 204, 206, 210 and 276 are all in parallel or side-by-side relation, as best shown in FIG. 19, and are all cemented 1n place by the cement 258. The lower end of the supply tub1ng 276 is permanently connected to the upper end of the bottom hole assembly 208, as by threading, and communicates with a passage 278 in the bottom hole assembly. This passage communicates at its lower end with a port 280 leading to an annulus 282 around a sleeve 284 pressed into the bottom hole assembly 208 in communication with the inlet tubing 204. The annulus 282 communicates with the lateral passage 238 leading to the oper-ating fluid ports 240 in the sealing collar 218. The

. 13 tubing system 202 is designed to receive the same pump 170 (not shown in FIGS. 18 to 20) as the tubing system 102. When such pump is in place in the tubing system 202, its operating fluid intake 174 receives operating fluid under pressure from the supply tubing 276 through the passage 278, the port 280, the annulus 282, the lateral passage 238 and the ports 240 in the sealing collar 218.

The lower end of the sleeve 284 communicates, through a pipe 286, with the upper end of a tubular member 232 corresponding yapproximately to the tubular fitting 132 and provided therein with an 4annular seat 236 for a cement plug, not shown, similar to the plug 162. In the tubing system 202, the cement distributing skirt 164 is omitted, and the cement discharge port 230 is located near the lower end of the bottom hole assembly 208, as shown in FIG. 18 of the drawings.

The well fluid admitted into the inlet tubing 204 from the perforations, not shown, leading to the productive formation, not shown, flows downwardly through the sleeve 284, the pipe 286, the tubular member 232 and the passage 244 into the lower end of the pump housing 212 below the inlet fitting 216, and thence upwardly through the inlet fitting 216 into the well fluid inlet 172 of the pump 170 when it is in its operating position within the pump housing 212.

In all other respects, the structure of the tubing system 202 is the same as the tubing system 102 so that a further description is not required. The operation of the tubing system 202 with the pump 170 installed, and the manners in which the pump is circulated into and out of the well 200, are substantially identical to those hereinbefore described.

TRANSITIONAL DISCUSSION The hereinbefore-described tubing systems of the invention which are illustrated in FIGS. 9 to 17 and FIGS. 18 to 20 are all closed systems, i.e., systems wherein the spent operating fluid is returned to the surface independently of the production fluid so that it can be re-used.

The remaining embodiments of the invention, viz., those illustrated in FIGS. 21 to 23, FIG. 24 and FIG. 25, relate to open systems wherein the production fluid and the spent operating fluid are commingled and conveyed to the surface in a single tubing. These open-system embodiments will now be considered in the sequence in which they are illustrated in the drawings.

FIGS. 21 to .Zi- Open system with two parallel tubings and one concentric tubing and with production up small tubing In these figures, a well 300 has installed therein a tubing system 302 comprising an inlet tubing 304 and a pump tubing 306 interconnected at their lower ends by a bottom hole assembly 308 in a manner to provide the same basic U-,tube arrangement as the embodiments previously described. The pump tubing 306 acts as the supply tubing and the flow of commingled production fluid and spent operating fluid is up a removable small tubing 376 concentrically set in the inlet tubing 304.

The bottom hole assembly 308 provides a pump housing 312 in alignment with the pump tubing 306, such pump housing having adjacent its lower end an annular seat 314 for an inlet fitting 316. This inlet fitting contains the usual standing valve, not shown, and is adapted to have a fluid operated pump, no t shown, seated thereon when such pump is in its operating position in the pump housing 312. As indicated above, the pump tubing 306 acts as the supply tubing for conveying operating fluid under pressure downwardly to the operating fluid intake of the pump. A fluid operated pump designed to receive operating fluid under pressure from the supply tubing 306 is used, an example of such a pump being disclosed in Patent No. 2,338,903, granted January l1, 1944 to Clarence I. Coberly, one of the applicants herein.

The bottom hole assembly 308 is provided therein with a cement discharge port 330 which communicates with the lower end of the inlet tubing 304. Below the port 330 is a tubular fitting 332, similar to the tubular tting 132, which is adapted to receive therein, and which is provided therein with an annularfseat 336 for a cement vplug corresponding to the plug 162. The tubing system 302 is cemented in place in the well 300 in substantially the same manner as the tubing system .102. The inlet tubing 304 is then perforated opposite `a productive formation 360 to provide perforations 368 establishing fluid communication between the productive formation and the interior of the inlet tubing at a level sufficiently above the lower end of the tubing system 302 to provide the desired gas-oil separation. The cementing and perforating operations are carried out in substantially the manners hereinbefore described in connection with the tubing system 102 so that further descriptions are not necessary.

The tubular fitting 332 is provided ltherein with a central, axial bore 334 into which a tubular fitting 378 may be stabbed and seated on the annular seat 336. The tubular fitting 378 is connected to the lower end of the removable production tubing 376, which is concentrically disposed within the inlet tubing 304, being installed after the `cementing and perforating operations have been performed. The tubular fitting 378 is provided with radial ports 380 which communicate with a lateral passage 338 in the bottom hole assembly 308 leading to the pump housing 312 above the annular seat 314 for the inlet fitting 316. When using a fluid loperated pump of the type disclosed in the aforementioned Patent No. 2,338,903, the production fluid discharged by the pump 'and the spent operating fluid discharged thereby are discharged into an annular clearance between the pump and the wall of the pump housing 312 in communication with the lateral -passage 338. Thus, the commingled production fluid and spent operating fluid flow through the lateral passage 338 and the radial ports 380 into the interior of the tubular fitting 378 and thence upwardly through the production tubing 376 to the surface.

The liquid components of the well fluid entering the inlet tubing 304 Ithrough the perforations 368 flow down wardly through the annulus between the inlet tubing and the production tubing 376, the gaseous components flowing upwardly through such annulus to the surface. As previously explained, this downward flow of the liquid components of the well fluid results in minimizing the amount of gas delivered to the well fluid inlet of a pump in the pump housing 312, the lower end of the tubing system 302 being located sufficiently below the perforations 368 to achieve the desired separation. From the annulus between the inlet and production tubings 304 and 376, the liquid components of the well fluid flow downwardly around the tubular fitting 378 and thence downwardly through a longitudinal passage 342 in the tubular fitting 332. From the passage 342, the liquid components of the well fluid flow through a connecting passage 344 leading to the lower end of the inlet fitting 316 on which the fluid operated pump is seated.

A pump of the type disclosed in the aforementioned Patent No. 2,338,903 is circulated into its operating position through the supply tubing 306, and is then operated, by operating fluid delivered through the supply tubing, to pump production fluid and spent operating fluid to the surface through the production tubing 376. When it is desired to remove the pump, fluid is introduced into the production tubing 376 and enters the pump housing 312 through the tubular fitting 378, the ports 380 and the lateral passage 338, to unseat the pump and displace it upwardly to the surface through the supply tubing 306.

The foregoing merely briefly describes the operation of the tubing system 302 of the invention, but it is thought that the over-all operation thereof will be clear in View of the similarity to the tubing systems hereinbefore described in detail.

FIG. 24.--Open system with three parallel tubilzgs and with production up large tubing The open system illustrated ,in this figure utilizes the basic tubing system 102 described previously, identilal reference numerals being utilized for identical parts. 1n -this embodiment, however, the concentric supply tubing 176 is omitted, and the tubing 110 is utilized as the Supply tubing. The pump tubing 106 is utilized as a large production tubing and conveys both the production uid and the spent operating fluid to the surface. The inlet tubing 104 performs the same function in this embodiment as in the embodiment of FIGS. 9 to 17.

The radial ports 140 in the sealing collar 118 are not used with the embodiment of FIG. 24, the lateral passage 138 leading to such ports being blocked by a plug 402 disposed in the central bore 134 in the tubular fitting 132 and seated on the annular seat 136. The plug 402 is provided with an upwardly extending stem 404 terminating in an enlarged, frusto-conical head 406 engageable by a suitable fishing tool on a wire line, not shown, to permit withdrawal of the plug 402 from the Well through the inlet tubing 104.

A fluid operated pump 410 is circulatable into and out of the well through the production tubing 106,` being seated on the inlet iitting 116 when in its operating position. To prevent unseating of the pump 410 by the pressure of the operating `fluid in the supply tubing 110, the passage 146 communicating with the lower end of the supply tubing is blocked below the lateral passage 148 -leading to the radial ports 150 in the sealing collar 118 by a check valve 412 seated onthe annular seat 1.52 This check valve prevents the pressure of the operating fluid from being applied to the downwardly facing annular area at the lower end of the pump 410 through the lateral passage 154.

The pump 410 is provided with an operating iluid intake 414 which communicates with the radial ports 150 in the Sealing collar 118 to receive operating uid under pressure from the supply tubing 110 by way of the vertical passage 146 and the lateral passage 148 in the bottom hole assembly 108. The pump 410 is provided with a well duid inlet 416 which is seated on and receives well duid through the inlet fitting 116. As in the previous embodiments, the U-tube connection between the inlet tubing 104 andthe tubing 106 below the level at which the inlet tubing is perforated insures the admission of relatively gas-free liquids to the pump 410 to permit it to operate at a high volumetric efliciency.

The production fluid and the spent operating fluid are discharged into an annular clearance between the pump 410 and the pump housing 112 through a production fluid outlet 418 and an operating uid exhaust 420, respectively. The comming-led production fluid and spent operating uid flow from such annular clearance into the 'pump housing 112 above the pump 410 through the lateral passage 124, the bypass passage 122, the lateral passage 128, and the radial ports 126 in the sealing collar 118;

From the radial ports 126 in the sealing collar 11S, the commingled production fluid and spent operating uid ow upwardly into the production tubing 106 around a packer mandrel 422 which extends upwardly from the pump 410, such packer mandrel being provided thereon with one or more downwardly-facing packer cups 424, only one of which is shown.` Below the lowest packer cup 424 are radial ports 426 which communicate with an axial passage 428 in the packer mandrel 422, such axial passage communicating with the interior of the production tubing 106 above the uppermost packer cup in a manner not specically shown. From this point, the commingled production iluid and spent operating uid ilow upwardly to ythe surface through the production tubing 106.

gages an annular seat `432 therein to cut ott communication between the radial ports 426 and the axial passage 428. The device 430 is disclosed in detail in patent application Serial No. 68,947, filed November 14, 1960, by Val Kogut and Coberly, now Patent No. 3,059,581, granted October 23, 1962. Reference thereto will provide a completel disclosure of the device 430 so that a disclosure thereof herein is not necessary.

Considering the operation of the embodiment of FIG. 24, the pump 410'` is circulated downwardly through the production tubing 106 into its operating position in the pump housing 112 by introducing fluid into the production tubing thereabove in the usual manner. It will be understood that when the pump 410 is circulated in, the

device 430 is in a position to permit upward flow through the packer mandrel 422.

The pump 410 is then operated by introducing operating fluid under pressure into the supply tubing 110, relatively gas-free well fluid from the inlet tubing 104 being drawn into the pump, and the production uid and the spent operating fluid being commingled and returned to the surface through the production tubing 106.

When it is desired to remove the pump 410, the upper end of` the supply tubing is closed, and fluid is introduced into the upper end of the production tubing 106 in sufficient quantity to develop a relatively high pressure therein. Such pressure acts on the device 430 and causes it to engage the annular seat 432 to prevent upward flow through the packer mandrel 422 past the packer cups 424. This accomplished, operating duid underpressure is again introduced into theV supply tubing 110 with the upper end of the production tubing 106 open. As disclosed in the aforementioned patent application Serial No. 68,947, operating fluid under pressure can now escape from the pump 410 through an axial passage434'and radial ports 436 in the packer mandrel 422, this being permitted` as the result of the previous actuation of the device 430. It will be noted that such operating uid is discharged into the production tubing 106 below the lowermost packer cup 424, and thus acts upwardly thereon to circulate the pump 410 upwardly to the surfacethrough the production tubing 106.

FIG. 25.-0pen system with three parallel tubngs and with production up small tubing The embodiment of the invention illustrated in this figure of the drawings also utilizes the tubing system 102, except that the concentric supply tubing 176 is omitted and communication between the inlet tubing 104 and the radial ports in the sealing collar 118 is prevented by theplug 402. In this case, the pump tubing 106 is the supply tubing and the small tubing 110 is the production tubing. One other difference between the embodiments of FIGS. 24 and 25 is that, in the embodiment of FIG. 25, the check valve 412 of FIG. 24 is omitted.

Hydraulically circulatable into and out of the well through the supply tubing 106 is a uid operated` pump 500 having at its upper end a packer mandrel 502 provided therein with an axial passage 504 for conveying operating .fluid under pressure from the interior of the supply tubing downwardly into the engine section of the pump. The pump 500 obtains relatively gas-free liquid from the inlet tubing 104 in the manner hereinbefore described, and discharges same as production duid which ows upwardly through the bypass passage 122, laterally through the lateral passage 128 and the radial ports 126 in the sealing collar 11S, downwardly through an annular space 506 between the pump 500 and the sealing collar 118, and then laterally through the radial ports in the sealing collar and the lateral passage 148 in the bottom hole housing into the vertical passage `146 leading upwardly to the production tubing 110. The spent operating fluid discharged by the pump 500 escapes into the annular space 506 through an operating fluid exhaust 50S and is commingled with the production iluid, being conveyed to the 17 surface therewith through the production tubing 110. The pump 500 is circulated into the well through the supply tubing 505 by introducing fluid into the supply tubing thereabove. To circulate the pump out of the well, fluid under pressure is introduced into the production tubing 110, acting on the lower end of the pump through the vertical passage 146 and the lateral passage 154 (not shown in FIG. 25).

CONCLUSION It will thus be apparent that the various embodiments of the invention illustrated in the drawings and hereinbefore described all use the basic concept of a U-shaped tubing system cemented in place in the well with the lower end of the U-tube sufficiently below the formation being produced to achieve satisfactory gas-oil separation as the oil ows downwardly through the inlet tubing to the well fluid inlet of a pump in the pump tubing.

Although various exemplary embodiments of the invention have been disclosed herein for purposes of illustration, it will be understood tha-t various changes, modifications and substitutions may be incorporated in such embodiments without departing from the spirit of the invention as defined by the claims which follow.

We claim l. A method of completing a well drilled from the surface at least into a productive formation, including the steps of:`

(a) setting in the well in side-by-side relation two tubings which are interconnected at their lower/ends, one yof said tubings being provided with a cement discharge opening therein adjacent its lower end and having a plug therein below said opening;

(b) flowing cement downwardly through said one tubing and discharging it through said opening until said tubings are cemented in place in the well opposite and adjacent the productive formation;

(c) purging said one tubing of cement;

(d) removing said plug from said one tubing; and

(e) perforating one of said tubings and the cement surrounding same opposite the productive formation and at a level above the lower ends of said tubmgs.

2. A method of completing a well drilled fromI the surface at least into a productive formation, including the steps of:

(a) setting' in thewell in side-by-sidevrelation two tubings which are interconnected at their lower ends, one of said tubings being provided with a cement discharge opening therein adjacent its lower end and having a removable plug seated therein below said opening;

(b) flowing cement downwardly through said one tubing and discharging it through said opening until said tubings lare cemented in place in the well opposite and adjacent the productive formation;

(c) circulating another removable plug down said one tubing to the removable plug first mentioned to purge said onetubing of cement;

(d) circulating said plugs upwardly through said one tubing to the surface; and

(e) perforating one of said 4tuhings and the cement surrounding same opposite the productive formation and at a level above the lower ends of said tubings.

3. A method of completing and pumping a well drilled from the surface at least into a productive formation capable of producing iiuid containing oil and gas, including l cement surrounding same opposite the productive formation and at a level above the lower ends of s'aid tubings;

(d) admitting uid from the productive formation into said one cemented tubing through the perforations formed during the step of subparagraph (c) hereof;

(e) producing gas from said fluid by conveying it upwardly through said one cemented tubing from said level td the surface; and

(f) producing 'oil from said uid by pumping it downwardly through said 'one cemented tubing from said level and then upwardly through another of said tubings 'to' the surface.

l 4. 'A producing installation for a well drilled from the surface at least into a productive formation, including:

(a) a tubing system,.comp'rising at least two tubings, extendingV downwardly in the well atleast into the productive formation;

(b) atleast two of said tubings being positioned side by side and being cemented in place in the well opposite and adjacent-the productive formation; j

(c) one of said cemented tubings and the cement surrounding same being perforated opposite the produci tiveforr'nationfand above the lower end of said one cemented tubing to establish fluid communication vbetween the productive formation and said one cemented tubing;

(d) means interconnecting` said one cemented tubing and another of saidvtubings in fluid communication ybelow the level of the perforations in said one cemented tubing; and p (e) pump means in said other tubing for pumping fluid downwardly lthrough said one cemented tubing and then upwardly to the surface through said other tubing.

5. A producing installation for a well drilled from the surface into a productive formation capable of producing oil and gas, including: ,e j

(a) a tubing system set in the well and comprising a U-tube having first and second tubular arms in sideby-side relation and interconnected at their lower ends; l

(b) means for admitting oil and gas from the well into said first tubular arm at an admission level above the interconnection between said lower ends of said tubular arms;

(c) said first tubular arm providing an elongated'y gasoil separating chamber extending downwardly from said admission level to said interconnection between said lower ends of :said tubular arms;

(d) pump means in one of said tubular arms for flowing oil downwardly through said separating chamber, through said interconnection between said lower ends of said tubular arms, and then upwardly lthrough said second tubular arm to the surface; and

(e) said first tubular arm constituting means for conveying gas upwardly from said separating chamber to the surface.

6. In a fluid operated pumping system for a well drilled from the surfacev at least into a productive formation, the combination of: Y

(a) a tubing system extending downwardly in the well at least into the productive formation and cemented in place in the well opposite and adjacent the productive formation; k Y

(b) said tubing system including a first, inlet tubing and a second, pump tubing in side-by-side relation;

(c) said tubing system including a bottom hole Aassembly connected to the lower ends of said inlet and pump tubings and interconnecting same in fluid communlcation;

(d) said bottom hole assembly providing a pump housing in alignment with and in communication with the lower end of said pump tubing;

(e) a fluid operatedfpump movable through said pump arcanes i9 tubing between the surface and an operating position in said pump housing;

(f) said pump having an inlet for well fluid which communicates with said inlet tubing when said pump is in its operating position in said pump housing;

(g) said tubing system and the cement surrounding same being provided with perforations therein opposite the productive formation which establish fluid communication between the productive formation and said inlet tubing to admit uid from the productive formation into said inlet tubing;

(h) said tubing system including a third tubing connected at its lower end to said bottom hole assembly in communication with said pump when said pump 1s in its operating position;

(i) one of said second and third tubings being a supply tubing for conveying operating iiuid under pressure for operating said pump downwardly in the well to said pump when said pump is in its operating position; and

(j) the other of said second and third tubings being a production'tubing for conveying upwardly to the surface production uid discharged by said pump when said pump is in its operating position.

7. In a iiuid operated pumping system for a well drilled from the surface at least into a productive formation, the combination of:

(a) tubing system extending downwardly in the well at least into the productive formation and cemented in place in the Well opposite and adjacent the productive formation;

(b) said tubing system including a first, inletv tubing and a second, pump tubing in side-by-side relation;

(c) said tubing system including a bottom hole assembly connected to the lower ends of said inlet and pump tubings and interconnecting same in fluid communication;

(d) said bottom hole assembly providing a pump housing in alignment with and in communication with the lower end of said pump tubing;

(e) a fluid operated pump movable through said pump tubing between the surface and an operating position in said pump housing;

(f) said pump having an inlet for well uid which communicates with said inlet tubing when said pump is in its operating position in said pump housing;

(g) said tubing system and the cement surrounding same being provided with perfor-ations therein opposite the productive formation which establish fluid communication between the productive formation and said inlet tubing to admit fluid from the productive formation into saidinlet tubing;

(li) said perforations being above said inlet of said pump when said pump is in its operating position;

(i) `said tubing system including a third tubing connected at its lower end to said bottom hole assembly in communication with said pump when said pump is in its operating position;

(j) one of said second and third tubings being a supply tubing for conveying operating fluid under pressure for operating said pump downwardly in the well to said pump when said pump is in its operating position; and

(k) the other of said second and third tubings being a production tubing for conveying upwardly to the surface production fluid discharged by said pump when said pump is in its operating position.

8. In a fluid operated pumping system for a well drilled from the surface at least into a productive formation, the combination of:

(a) a tubing system extending downwardly in the well at least into the productive formation and cemented in place in the well opposite and adjacent the productive formation;

(b) said tubing system yincluding a first, inlet tubing 2t? and a second, pump tubing in side-by-side relation;

(c) said tubing system including a bottom hole assembly connected to the lower yends of said inlet and pump tubings and interconnecting same in tiuid cornmunication;

(d) said bottom hole assembly providing a pump housing in alignment with and in communication with the lower end of said pump tubing;

(e) a fluid operated pump movable through said pump tubing between the surface and an operating position in said pump housing;

(f) said pump having an inlet for well fluid which communicates with said inlet tubing when said pump is in its operating position in said pump housing;

(g) said inlet tubing and the cement surrounding same being provided therein, opposite the productive formation and above said bottom hole assembly, with perforations which establish fluid communication between the productive formation and said inlet tubing to admit iiuid from the productive formation into said inlet tubing;

(l1) said perforations being above said inlet of said pump when said pump is in its operating position;

(i) said tubing system including a third tubing connected at its lower end to said bottom hole assembly in communication with said pump when said pump is in its operating position;

(j) one of said second and third tubings being a supply1 tubing for conveying operating fluid under pressure for operating said pump downwardly in the well to said pump when said pump is in its operating position; and

(k) the other of said second and third tubings being a production tubing for conveying upwardly to the surface production fluid discharged by said pump when said pump is in its operating position.

9. A iiuid operated pumping system as defined in claim 8 wherein said third tubing is within said lirst, inlet tubing.

10. A liuid operated pumping system as deiined in claim 8 wherein said third tubing is alongside said lirst, inlet tubing and said second, pump tubing.

ll. In a fluid operated pumping system for a well drilled from the surface at least into a productive forma- Y tion, the combination of:

. (a) a tubing system extending downwardly in the well at least into the productive formation and cemented in place in the well opposite and adjacent the productive lformation;

(b) said tubing system including a first, inlet tubing and a second, pump tubing in side-by-side relation;

(c) said tubing system including a bottom hole assembly connected to the lower ends of said inlet and pump tubings and interconnecting same in liuid communication;

(d) said bottom hole assembly providing a pump housing in alignment with and in communication with the lower end of said pump tubing; Y

(e) a uid operated pump movable through said pump tubing between the surface and an operating position in said pump housing;

(f) said pump having an inlet for Well uid which communicates with said inlet tubing when said pump is in its operating position in said pump housing;

(g) said inlet tubing and the cement surrounding same being provided therein, opposite the productive formation and above said bottom hole assembly, with perforations which establish fluid communication between the productive formation and said inlet tubing to admit iiuid from the productive formation into said inlet tubing;

(h) said perforations being above -said inlet of said pump when said pump is in`its operating position;

(i) said tubing system including third and fourth tubings connected at their lower ends to said bottom A h`ole`assemb1y in communication with said pump when said pump is in its operating position;

(j) one of said second, third and fourth tubings being a supply tubing for conveying operating fluid under pressure for operating said pump downwardly in the well to said pump when said pump is in its operating position;

(k) another of said second, third and fourth tubings being a production tubing for conveying upwardly to the surface production uid discharged by said pump when said pump is in its operating position; and

(l) the remaining one of `said second, third and fourth 22 tubings being a return tubing vtnconveying upwardly to the surface spent operating fluid discharged by said pump when it is in its operating position.

References Cited in the tile of this patent UNITED STATES PATENTS 2,652,130 Ferguson Sept. 15, 1953 2,923,357 Dafn Feb. 2, 1960 3,025,798 Coberly et al Mar. 20, 1962 3,032,104 OReilly May 1, 1962 3,036,634 Corley May 29, 1962 3,054,456 Hammaker Sept. 18, 1962 3,086,592 Hoch Apr. 23, 1963 

1. A METHOD OF COMPLETING A WELL DRILLED FROM THE SURFACE AT LEAST INTO A PRODUCTIVE FORMATION, INCLUDING THE STEPS OF: (A) SETTING IN THE WELL IN SIDE-BY-SIDE RELATION TWO TUBINGS WHICH ARE INTERCONNECTED AT THEIR LOWER ENDS, ONE OF SAID TUBINGS BEING PROVIDED WITH A CEMENT DISCHARGE OPENING THEREIN ADJACENT ITS LOWER END AND HAVING A PLUG THEREIN BELOW SAID OPENING; (B) FLOWING CEMENT DOWNWARDLY THROUGH SAID ONE TUBING AND DISCHARGING IT THROUGH SAID OPENING UNTIL SAID TUBINGS ARE CEMENTED IN PLACE IN THE WELL OPPOSITE AND ADJACENT THE PRODUCTIVE FORMATION; (C) PURGING SAID ONE TUBING OF CEMENT; (D) REMOVING SAID PLUG FROM SAID ONE TUBING; AND (E) PERFORATING ONE OF SAID TUBINGS AND THE CEMENT SURROUNDING SAME OPPOSITE THE PRODUCTIVE FORMATION AND AT A LEVEL ABOVE THE LOWER ENDS OF SAID TUBINGS. 